<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>纵向重叠</title>
  <style type="text/css">
    p{
      font-size: 16px;
      line-height: 1;
      margin-top: 10px;
      margin-bottom: 15px;
    }
  </style>
</head>
<body>
  <p>AAA</p>
  <p></p>
  <p></p>
  <p></p>
  <p>BBB</p>
  <ul>
    <li>margin-top 和 margin-bottom 会发生重叠</li>
    <li>空白内容的 p标签 也会重叠</li>
  </ul>
    
</body>
</html>